High-intensity Interval Exercise Protocol Research Articles

Changes in the reactive hyperemia index after continuous and interval exercise.

High-intensity interval exercise (HIIE) is more effective than moderate-intensity interval exercise (MICE) for improving macrovascular function (e.g., flow-mediated dilation), but less is known regarding the effect of HIIE on microvascular function. We used peripheral artery tonometry to measure the reactive hyperemia index (RHI) and examine the acute effects of HIIE and MICE on microvascular function. Ten healthy participants (50% men, age: 26 ± 5 years, mass: 75.6 ± 15.1 kg, height: 170 ± 10 cm, body mass index: 26.0 ± 3.1 kg∙m-2) performed single bouts of HIIE and MICE cycling on separate occasions. The MICE protocol was 20 min at 60% of maximum power output. The HIIE protocol was a 12-min warm up at 50% of maximum power output immediately followed by an 8-min Tabata protocol where participants alternated between cycling at ⩾ 100% max power (20 sec) and rest (10 sec). The RHI was measured before, immediately after, and 1 h after exercise and compared by two-way repeated measures analysis of variance (condition [MICE, HIIE] and time [pre-, post-, and 1-h postexercise]). Compared to baseline, RHI increased 1 h after MICE only (p = 0.02). Heart rate was higher during MICE at 5 and 10 min (p = 0.02) and higher during HIIE at min 20 (p < 0.01). Within a sample of healthy adults, the RHI was improved 1 h after a single session of MICE but not HIIE. Future research is needed to determine the significance of the differential effects of exercise regimens on the macro- and microvasculature.

Neural and Muscular Determinants of Performance Fatigability Are Independent of Work and Recovery Durations During High-Intensity Interval Exercise in Males

ABSTRACT The present study aimed to investigate the effect of two protocols of high-intensity interval exercise (HIIE) on performance fatigability and its neural and muscular determinants. On different days, 14 healthy males performed two HIIE protocols with different work and recovery durations (matched for total duration, work and recovery intensities, and density): 1) 4 × 4 min at 90% HRpeak,180-s recovery at 70% HRpeak; and 2) 16 × 1 min at 90% HRpeak, 45-s recovery at 70% HRpeak. Pre- to post-HIIE reduction in maximal voluntary isometric contraction (MVIC) was used as marker of performance fatigability, while voluntary activation (VA) and potentiated quadriceps twitch force (Qtw) as markers of the neural (i.e. central fatigue) and muscular (i.e. peripheral fatigue) determinants, respectively. In addition, pre- to post-HIIE reduction in twitch force stimulated at 100 Hz (Qtw100) and 10:100 Hz ratio (Qtw10:Qtw100) were used as markers of high- and low-frequency performance fatigability, respectively. The MVIC, VA, Tw, Qtw100, and Qtw10:Qtw100 ratio decreased similarly from pre- to post-HIIE in both HIIE protocols (p < .05). The rating of perceived effort, blood pH, and plasma lactate responses were similar between HIIE protocols (p > .05), but the heart rate was higher in the longer HIIE protocol (p < .05). In conclusion, performance fatigability and its neural and muscular determinants seemed to be independent of the work and recovery durations of the HIIE, at least when HIIE protocols were matched for total work duration, work and recovery intensities, and density. Further, HIIE with long work and recovery might be preferable when the intention is to stress the chronotropic response.

Delaying post-exercise carbohydrate intake impairs next-day exercise capacity but not muscle glycogen or molecular responses.

To investigate how delayed post-exercise carbohydrate intake affects muscle glycogen, metabolic- and mitochondrial-related molecular responses, and subsequent high-intensity interval exercise (HIIE) capacity. In a double-blind cross-over design, nine recreationally active men performed HIIE (10 × 2-min cycling, ~94% W˙peak) in the fed state, on two occasions. During 0-3 h post-HIIE, participants drank either carbohydrates ("Immediate Carbohydrate" [IC], providing 2.4 g/kg) or water ("Delayed Carbohydrate" [DC]); total carbohydrate intake over 24 h post-HIIE was matched (~7 g/kg/d). Skeletal muscle (sampled pre-HIIE, post-HIIE, +3 h, +8 h, +24 h) was analyzed for whole-muscle glycogen and mRNA content, plus signaling proteins in cytoplasmic- and nuclear-enriched fractions. After 24 h, participants repeated the HIIE protocol until failure, to test subsequent HIIE capacity; blood lactate, heart rate, and ratings of perceived effort (RPE) were measured throughout. Muscle glycogen concentrations, and relative changes, were similar between conditions throughout (p > 0.05). Muscle glycogen was reduced from baseline (mean ± SD mmol/kg dm; IC: 409 ± 166; DC: 352 ± 76) at post-HIIE (IC: 253 ± 96; DC: 214 ± 82), +3 h (IC: 276 ± 62; DC: 269 ± 116) and + 8 h (IC: 321 ± 56; DC: 269 ± 116), returning to near-baseline by +24 h. Several genes (PGC-1ɑ, p53) and proteins (p-ACCSer79, p-P38 MAPKThr180/Tyr182) elicited typical exercise-induced changes irrespective of condition. Delaying carbohydrate intake reduced next-day HIIE capacity (5 ± 3 intervals) and increased RPE (~2 ratings), despite similar physiological responses between conditions. Molecular responses to HIIE (performed in the fed state) were not enhanced by delayed post-exercise carbohydrate intake. Our findings support immediate post-exercise refueling if the goal is to maximize next-day HIIE capacity and recovery time is ≤24 h.

The Effect of Low-Intensity Interval Exercise with Blood Flow Restriction on Plasma Cardiac Troponin: A Cross-Design Trial.

Low-intensity training with blood flow restriction (BFR) training could induce endurance adaptations, its impact on myocardial markers is still unclear compared to training without BFR. Consequently, the influence of low-intensity interval exercise with and without BFR and high-intensity interval exercise (HIIE) on cardiac troponin was determined in this study. Twelve physically active males between 18 and 26 years volunteered as participants. The participants completed 3 exercise tests in random order, which included 40% VO2max low-intensity cycling without BFR (group L), 40% VO2max low-intensity cycling with BFR set at 60% limb occlusion pressure (LOP) (group B), and 80% VO2max high-intensity cycling without BFR (group H). Participant muscle oxygen, blood flow, oxygen uptake, heart rate (HR), perceived exertion (RPE) rating, and pain levels were determined before and after exercise, after cuff inflation, and pre- and post-each exercise. Moreover, before each protocol, immediately after the exercises, and 3-4 hours after each exercise, elbow vein blood samples were collected to evaluate lactate (LA) and high-sensitivity cardiac troponin T (cTnT). Increased LA was recorded after exercise by the individuals in group H, which was more significant than in group B. Moreover, group B documented a more significant LA increment than group L (P < .05). The peak cTnT of groups B and H after exercise was significantly higher (P < .05). Furthermore, the increase was more significant than the values recorded by group L (P < .05). The present study demonstrated that low-intensity interval exercise combined with BFR could cause cTnT elevations compared to training without BFR. The increase was similar to HIIE protocols.

The Effect of High Intensity Interval Exercise on Platelet Engraftment in Autologous Bone Marrow Transplantation (BMT).

Background: Thrombocytopenia is a frequent complication after hematopoietic stem cell transplantation (HSCT). Although platelet transfusion is the most used treatment for severe thrombocytopenia, it is associated with well-established risks. High-intensity interval exercise (HIIE) results in thrombocytosis. Therefore, this study aimed to reduce thrombocytopenia by increasing platelet count through exercise. Materials and Methods: Twenty lymphoma and multiple myeloma patients were divided into HIIE and control groups. To determine the maximal exercise capacity, patients in the HIIE group performed a graded exercise test. All patients received granulocyte colony-stimulating factor for 5 days,followed by a HIIE trial. After 5 min warm up at 10 to 20% of peak power, patients in the HIIE group performed an HIIE protocol that included 12 intervals of one-minute work at 100% peak power interspersed by one-minute active rest at 20% of peak power. Patients in the control group were seated for the same duration without any physical activity. Two blood samples were taken before and immediately after the trials and were analyzed for measuring complete blood count. Results: Platelet count on the day of platelet engraftment in the HIIE group was significantly higher than in the control group (P=0.02). Single-donor platelet transfusion was significantly lower in the HIIE group than in the control group (P=0.05). Conclusion: Based on the findings of the present study, a short bout of HIIE had a positive effect on platelet engraftment through thrombocytosis and reduced platelet transfusion and its complications, which could be a useful strategy for HSCT patients.

Feasibility of a Recumbent Stepper for Short-Interval, Low-Volume High-Intensity Interval Exercise in Stroke.

Studies investigating high-intensity interval exercise (HIIE) in stroke typically emphasize treadmill training. However, a literature review suggested that seated devices such as a recumbent stepper or cycle offer a promising alternative for HIIE since exercise can be prescribed using peak power output (PPO). Therefore, this would give health care professionals the ability to monitor and adapt power output for the target heart rate range. The purpose of this secondary analysis was to examine the feasibility of prescribing short-interval, low-volume HIIE using PPO in chronic stroke. We used several methods to test feasibility: (1)Acceptability: Measured by the percentage of participants who completed the entire HIIE protocol; (2) Implementation was assessed by the number of reported cardiac or serious adverse events during submaximal exercise testing and HIIE and the average percentage of participants reaching vigorous intensity, defined by the American College of Sports Medicine as at least 77% of age-predicted maximal heart rate (HRmax). Data were available for 28 participants who were 32.2 (17.2) months post-stroke and 61.4 (11.9) years of age. Twenty-eight participants completed HIIE per protocol. No cardiac or serious adverse events occurred during the submaximal exercise test or during HIIE. The rapid switching between HIIE and recovery showed no evidence of blood pressure reaching unsafe thresholds. Average intensity during HIIE reached 76.8% HRmax, which is slightly below the target of 77.0%. A single bout of short-interval, low-volume HIIE, prescribed using PPO, was feasible in chronic stroke.

High Intensity Interval Exercise Causes Acute Microvascular Dysfunction in Elderly Individuals with Low Cardiorespiratory Fitness - A Pilot Study

Background: Frailty is strongly associated with low physical and cardiorespiratory fitness, and unfortunately is observed in 20-50% of the ~50 million adults that experience surgical stress in the U.S. each year. The peripheral microvasculature may serve as a potential target to increase resilience to stress and improve postoperative outcomes. A better understanding of how the microvasculature responds to stress in elderly individuals with low fitness is thus needed. Objective: To define the relationship between cardiorespiratory fitness and microvascular resiliency to stress in elderly individuals. Hypothesis: Elderly individuals with low cardiorespiratory fitness will show acute reductions in acetylcholine (Ach)-mediated dilation of the skin microvasculature following the physiological stressful stimulus of high intensity interval exercise (HIIE). Methods: This was a prospective, observational study that enrolled elderly individuals aged 65-85 years from the community. Each participant was asked to complete two study visits. During visit 1, participants completed the Frailty Index and performed a graded cardiopulmonary exercise test (CPET) on a cycle ergometer with a metabolic cart to measure peak total body oxygen consumption (VO2 Peak). During visit 2, laser Doppler flowmetry with dermal microdialysis was performed on the ventral forearm to measure peak cutaneous microvascular vasodilation to Ach (10 mM). After baseline assessment, the participants performed a HIIE protocol where they repetitively switched between exercising at 70% of the peak workload achieved during the CPET for 60 seconds, followed by a 60 second active recovery at 10 watts. These intervals were repeated 12 times, for a total exercise duration of 24 min. Thirty minutes following exercise, Ach-mediated dilation of the cutaneous microvasculature was reassessed. Maximum dilator capacity of each site was assessed by infusing sodium nitroprusside (28 mM) and heating the skin to 43 °C. Results: Six individuals (1 male, 5 females; mean age 68 ±4 years) completed all study procedures. Based on age- and sex-predicted normative values for VO2 Max, three of the individuals had high physical fitness while three had low fitness (mean VO2 Peak = 27.5±1.1 vs. 13.6±3.4 ml/kg/min, respectively). Prior to HIIE there was no difference in peak dilation to Ach between the individuals with high vs. low fitness (% max dilation = 72±13 vs. 83±13, respectively). During HIIE, the individuals reached a Borg rating of perceived exertion of 15±4 (out of 20) and their peak heart rate was 74±15% of their age-predicted maximum. Ach-mediated dilation of the dermal microvasculature was reduced following HIIE in elderly individuals with low cardiorespiratory fitness (pre vs. post % maximum dilation = 82±13 vs. 49±27, respectively; mean change = -34±40 %) but unchanged in those with high fitness (pre vs. post % maximum dilation = 72±13 vs. 78±10, respectively; mean change = 5±3 %). Using Pearson correlation tests there was a strong correlation between the change in peak Ach-mediated dilation pre vs. post HIIE and both VO2 Peak (r=0.82, p=0.04) and Frailty Index score (r=-0.98, p&lt;0.001). Conclusion: Microvascular resilience to acute stress is decreased in elderly individuals with low cardiorespiratory fitness compared to those with high fitness. None. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Acute effect of moderate and high-intensity interval exercises on asprosin and BDNF levels in inactive normal weight and obese individuals

This study aimed to examine the acute effects of moderate-intensity aerobic and high-intensity interval exercise protocols on Asprosin and Brain-Derived Neurotrophic Factor (BDNF) levels in inactive normal weight and obese individuals. A total of 20 male individuals aged 18–65 years, ten normal weight (NW) (Body Mass Index (BMI): 18.5–24.99 kg/m2) and 10 obese (Ob) (BMI: 24.99–35.00 kg/m2) participated in this study, voluntarily. Moderate aerobic exercise (AE) (main circuit 30 min, between 40 and 59% of Heart Rate Reserve: HRR) and High-Intensity Interval exercise (HIIE) running protocols (main circuit 20 min, between 75 and 90% of the HRR for 1 min*10 times, and 1-min active rest at 30% of the HRR) was applied to the volunteer participants in the morning hours (08.00–10.00 a.m.), following the night fasting (at least 8–10 h) for at least 3 days between each other. Blood samples were collected from the participants before and immediately after each exercise protocol, and serum asprosin and BDNF hormone levels were determined by Enzyme-Linked Immunosorbent Assay” method. Basal serum asprosin was found to be significantly higher in the Ob group compared to the NW group (p < .001), while the basal serum BDNF hormone was found to be lower (p < 0.05). It was observed that the serum asprosin level of both groups decreased significantly after both AE and HIIE protocols (p < 0.05). In addition, there was a significantly higher decrease in serum asprosin level in the Ob group compared to the NW group after HIIE protocol. For the Ob group, serum BDNF level increased considerably after HIIE protocol compared to AE protocol (p < 0.05). Serum asprosin was found to be higher in the Ob group, while the serum BDNF was found to be lower. In addition, the acute exercises of different intensity significantly affected hormones that regulate appetite metabolism. In particular, it was observed that the HIIE protocol had a greater effect on the regulation of appetite (hunger-satiety) in the Ob group. This result can be taken into account when planning training programs for these individuals.

Acute physiological responses to high-intensity interval exercise in patients with coronary artery disease.

Time spent closer to maximal effort during exercise is a potent stimulus for cardiorespiratory adaptations. The primary purpose was to determine which high-intensity interval exercise (HIIE) protocol provided the greatest physiological stimulus by comparing time spent ≥ 90% peak oxygen consumption (V̇O2peak) and heart rate reserve (HRR) in patients with coronary artery disease (CAD) in response to 3 HIIE protocols and the exercise standard of care, moderate-intensity continuous exercise (MICE). A secondary purpose was to assess protocol preference. Fifteen patients with CAD (6 females, 67 ± 6years) underwent measurements of V̇O2 and heart rate during MICE and three HIIE protocols all performed on a treadmill. The HIIE protocols included one with long intervals (4 × 4-min), short intervals (10 × 1-min), and an adapted version of the 4 × 4 [Toronto Rehabilitation Institute Protocol, (TRIP)]. Time spent ≥ 90% V̇O2peak and HRR were compared. Time spent ≥ 90% V̇O2peak was higher during 4 × 4 (6.3 ± 8.4min) vs. MICE (1.7 ± 3.9min; P = 0.001), while time spent ≥ 90% HRR was higher during 4 × 4 (6.0 ± 5.3min) vs. MICE (0.1 ± 0.2min; P < 0.001) and 10 × 1 (0.7 ± 0.8min; P = 0.016). TRIP had similar responses as 10 × 1 and MICE. The 10 × 1 was the most preferred protocol and the 4 × 4 was the least preferred protocol. Longer intervals (4 × 4) provided the greatest physiological stimulus compared to the exercise standard of care and shorter intervals. However, this protocol was least preferred which may impact exercise adherence. Although the physiological stimulus is important to maximize training adaptations, exercise preferences and attitudes should be considered.

Higher Oxygen Uptake And Heart Rate Response In Recovery From Acute High Intensity Interval Exercise

Optimizing energy expenditure is paramount to achieving negative energy balance and promoting weight loss. High intensity interval exercise (HIIE) has been popularized for its ability to reduce body fat despite its time efficiency, yet it is unknown if the majority of calories burned during acute HIIE stems from completion of each interval or subsequent recovery period. Moreover, it is thought that the adaptive response to HIIE is mediated by the acute metabolic stress, but it is unknown if this stems from the interval or recovery phase of training. PURPOSE: To compare oxygen uptake (VO2) and heart values (HR) acquired during HIIE and in subsequent recovery to various HIIE regimens. METHODS: Data from 6 previously-published studies requiring various cycling-based HIIE regimens were analyzed from 89 healthy and active men and women (age, BMI, PPO, and VO2max = 25 ± 6 yr, 24 ± 3 kg/m2, 276 ± 59 W, and 40 ± 7 mL/kg/min). HIIE protocols included six to twelve 30 s - 2.5 min efforts at intensities ranging from 70 - 85 %PPO, with recovery periods ranging from 30 - 75 s. During exercise, VO2, HR, and blood lactate concentration (BLa) were acquired. RESULTS: HIIE bouts elicited peak HR, VO2, and BLa equal to 90 ± 6 %HRmax, 76 ± 12 %VO2max, and 10 ± 4 mM, respectively, and calorie expenditure was equal to 173 ± 47 kcal. Paired t-test revealed significantly higher VO2 (1.95 ± 0.46 L/min vs. 2.02 ± 0.46 L/min, p < 0.001) and HR (158 ± 14 b/min vs. 161 ± 15 b/min, p < 0.001) during recovery from acute HIIE versus the intervals. Significant inverse associations were demonstrated between VO2max and peak VO2 (r = -0.40, p < 0.001) and peak HR (r = -0.30, p = 0.004) attained during HIIE. CONCLUSIONS: Data reveal a significantly higher VO2 during recovery from HIIE compared to each interval, which may be due to slow O2 kinetics of these average fitness adults. HR was also higher in recovery suggesting a severe stress on the cardiovascular system not only during each interval, but also in recovery despite the low power outputs completed. More fit participants showed a blunted VO2 and HR response to HIIE suggesting that they may be at lower relative intensities versus less fit individuals. The structure of recovery periods as well as the interval efforts may be modified by clinicians to optimize calorie expenditure and metabolic stress of acute HIIE.

Interleukin-6, undercarboxylated osteocalcin, and brain-derived neurotrophic factor responses to single and repeated sessions of high-intensity interval exercise

ObjectivesThe purpose of this study was to compare the effects of a single session of high-intensity interval exercise (HIIE) with 2 consecutive HIIEs, separated by 3 h of recovery, on plasma interleukin-6 (IL-6), undercarboxylated osteocalcin (ucOC), and brain-derived neurotrophic factor (BDNF) responses. MethodsTwenty male recreational endurance athletes completed two HIIE trials in a randomized crossover design: a single session of HIIE on the single exercise day (HIIE-S) and two sessions of HIIE 3 h apart on the double exercise day (HIIE-D). The HIIE protocol consisted of 10 × 1 min cycling at 100 % of peak oxygen uptake, with 75 s of low-intensity cycling at 60 W. Blood samples were collected to analyze IL-6, ucOC, and BDNF levels before and immediately after HIIE on the HIIE-S and before and immediately after the second HIIE on the HIIE-D. ResultsBoth HIIE interventions significantly increased (p < 0.001) plasma IL-6 (HIIE-S 33.90 % vs HIIE-D 31.04 %; p = 0.64), ucOC (HIIE-S 37.18 % vs HIIE-D 39.54 %; p = 0.85), and BDNF levels (HIIE-S 236.01 % vs HIIE-D 216.68 %; p = 0.69), with no group effect. ConclusionsOur results demonstrate that performing two consecutive HIIEs on the same day with a 3-h rest results in similar changes in plasma levels of IL-6, BDNF, and ucOC compared with a single session of HIIE.

Royal Jelly Plus Coenzyme Q10 Supplementation Enhances High-Intensity Interval Exercise Performance via Alterations in Cardiac Autonomic Regulation and Blood Lactate Concentration in Runners.

PurposeThis study aimed to examine whether oral royal jelly (RJ) and coenzyme Q10 (CoQ10) co-supplementation could improve high-intensity interval exercise (HIIE) performance in runners, reducing exercise-induced lactic acidosis and decreasing elevated sympathetic tone following exercise.MethodsThirty regional-level runners (age: 19 ± 1 years; height: 173 ± 2 cm; body mass: 68.9 ± 2 kg; body mass index: 23.1 ± 1 kg/m2) were randomly allocated to receive either 400 mg of RJ and 60 mg of CoQ10 (RJQ) or matching placebo (PLA) once daily for 10 days. Exercise performance expressed as time taken to complete HIIE was evaluated at baseline, and then reassessed at day 10 of intervention. HIIE protocol applied to the runners included three repetitions of 100 m distance at maximum possible speed interspersed with 45 s of recovery periods. Indices of heart rate variability and blood lactate concentration were also measured before and immediately after HIIE in each group.ResultsHIIE performance significantly improved in RJQ group (p = 0.005) compared to PLA group. Blood lactate levels and sympathetic influence on the heart were significantly lower both before and after the HIIE in athletes who received RJQ (p < 0.05) compared to PLA. Regression analysis showed that oral RJQ administration for 10 days was significantly associated with reductions in HIIE-induced increases in blood lactate concentration and enhanced cardiac parasympathetic modulation following exercise compared to PLA. Principal component analysis revealed that runners treated with RJQ are grouped by the first two principal components into a separate cluster compared to PLA. Correlation analysis demonstrated that the improvements in runners’ HIIE performance were due in significant part to RJQ-induced reduction of increment in blood lactate levels in response to exercise in combination with a more rapid shift in autonomic activity toward increased parasympathetic control early at post-exercise.ConclusionThese findings suggest that RJQ supplementation for 10 days is potentially effective for enhancing HIIE performance and alleviating adverse effects of increased intramuscular acidity and prolonged sympathetic dominance following intense exercise.

Royal jelly plus coenzyme Q10 supplementation improves high-intensity interval exercise performance via changes in plasmatic and salivary biomarkers of oxidative stress and muscle damage in swimmers: a randomized, double-blind, placebo-controlled pilot trial.

ABSTRACTBackgroundExcessive production of free radicals caused by many types of exercise results in oxidative stress, which leads to muscle damage, fatigue, and impaired performance. Supplementation with royal jelly (RJ) or coenzyme Q10 (CoQ10) has been shown to attenuate exercise-induced oxidant stress in damaged muscle and improve various aspects of exercise performance in many but not all studies. Nevertheless, the effects of treatments based on RJ plus CoQ10 supplementation, which may be potentially beneficial for reducing oxidative stress and enhancing athletic performance, remain unexplored. This study aimed to examine whether oral RJ and CoQ10 co-supplementation could improve high-intensity interval exercise (HIIE) performance in swimmers, inhibiting exercise-induced oxidative stress and muscle damage.MethodsTwenty high-level swimmers were randomly allocated to receive either 400 mg of RJ and 60 mg of CoQ10 (RJQ) or matching placebo (PLA) once daily for 10 days. Exercise performance was evaluated at baseline, and then reassessed at day 10 of intervention, using a HIIE protocol. Diene conjugates (DC), Schiff bases (SB), and creatine kinase (CK) were also measured in blood plasma and saliva before and immediately after HIIE in both groups.ResultsHIIE performance expressed as number of points according to a single assessment system developed and approved by the International Swimming Federation (FINA points) significantly improved in RJQ group (p = 0.013) compared to PLA group. Exercise-induced increase in DC, SB, and CK levels in plasma and saliva significantly diminished only in RJQ group (p < 0.05). Regression analysis showed that oral RJQ administration for 10 days was significantly associated with reductions in HIIE-induced increases in plasmatic and salivary DC, SB, and CK levels compared to PLA. Principal component analysis revealed that swimmers treated with RJQ are grouped by both plasmatic and salivary principal components (PC) into a separate cluster compared to PLA. Strong negative correlation between the number of FINA points and plasmatic and salivary PC1 values was observed in both intervention groups.ConclusionThe improvements in swimmers’ HIIE performance were due in significant part to RJQ-induced reducing in lipid peroxidation and muscle damage in response to exercise. These findings suggest that RJQ supplementation for 10 days is potentially effective for enhancing HIIE performance and alleviating oxidant stress.AbbreviationsRJ, royal jelly; CoQ10, coenzyme Q10; HIIE, high-intensity interval exercise; DC, diene conjugates; SB, Schiff bases; CK, creatine kinase; RJQ, royal jelly plus coenzyme Q10; PLA, placebo; FINA points, points according to a single assessment system developed and approved by the International Swimming Federation; ROS, reactive oxygen species; 10H2DA, 10-hydroxy-2-decenoic acid; AMPK, 5′-AMP-activated protein kinase; FoxO3, forkhead box O3; MnSOD, manganese-superoxide dismutase; CAT, catalase; E, optical densities; PCA, principal component analysis; PC, principal component; MCFAs, medium-chain fatty acids; CaMKKβ, Ca2+/calmodulin-dependent protein kinase β; TBARS, thiobarbituric acid reactive substances; MDA, malondialdehyde.

Effect of high-intensity interval exercise on renal artery hemodynamics in healthy young adults.

High-intensity interval exercise is useful for sustained exercise; however, its effect on renal artery hemodynamics is unclear. This study aimed to evaluate changes in renal artery blood flow velocity due to high-intensity interval exercise. Ten healthy adults (age, 23.5±1.2 years) completed high-intensity interval exercise and moderate-intensity continuous exercise protocols on separate days. The high-intensity interval exercise protocol (total duration, 26 min) comprised eight sets of high-intensity exercise sessions at 85% maximum oxygen uptake for 1 min, with intervals of 40% maximum oxygen uptake for 2 min between sets. The moderate-intensity continuous exercise protocol comprised 40 min of exercise at 40% maximum oxygen uptake. Renal artery blood flow velocity and natural log-transformed high frequency spectral power (an index of cardiac parasympathetic nervous system activity) were measured before and after exercise. Additionally, exercise enjoyment was measured using a questionnaire. Renal artery blood flow velocity did not significantly differ between protocols or timepoints for either protocol. However, the natural log-transformed high frequency spectral power was significantly lower with high-intensity interval exercise than with moderate-intensity continuous exercise (P<0.001, F=25.97) during exercise and at 10 min after exercise, and it did not return to pre-exercise levels with high-intensity interval exercise. Moreover, there was no significant difference in exercise enjoyment between the two protocols. In healthy young adults, high-intensity interval exercise reduces parasympathetic activity; however, it does not produce any significant changes in renal artery hemodynamics after exercise.

Melatonin reduces muscle damage, inflammation and oxidative stress induced by exhaustive exercise in people with overweight/obesity.

Intense physical exercise leads to inflammation, oxidative stress and muscle damage, and these responses are of greater magnitude in people with obesity. Melatonin (MLT) is considered an endogenous antioxidant which may have beneficial effects against inflammation, oxidative stress and promote tissue repair after exercise. The aim of this study was to examine the effect of MLT on inflammatory parameters, oxidative stress and muscle damage in people with overweight/obesity after a high-intensity interval exercise (HIIE). A total of 23 subjects with obesity (9 men and 14 women) age: 33.26 ± 9.81 years, BMI: 37.75 ± 8.87 kg.m-2 were randomized to participate in two experimental sessions: HIIE + Placebo and HIIE + MLT (3 mg). The HIIE protocol corresponds to 8 intervals of 1 min (90% of the maximal aerobic power (MAP)) alternating with 2 min recovery (45% of the MAP). Blood samples were drawn before and 5 min after each exercise session. MLT ingestion attenuated the increase of inflammation (C-reactive protein, white blood cells (P < 0.001, ηp2 = 0.45; for both) and Neutrophils (P < 0.01, ηp2 = 0.36)) and hepatic and muscle damage (Aspartate aminotransferase (P < 0.01, ηp2 = 0.25), Alanine aminotransferase (P < 0.01, ηp2 = 0.27) and Creatine kinase (P = 0.02, ηp2 = 0.23). MLT also attenuated the exercise induced lipid and protein peroxidation (i.e., Malondialdehyde (P = 0.03, ηp2 = 0.19) and AOPP (P < 0.001, ηp2 = 0.55)). Concerning the antioxidant status, MLT intake increased Thiol (P < 0.01, ηp2 = 0.26) and Catalase (P < 0.01, ηp2 = 0.32) and decreased Uric acid (P = 0.02, ηp2 = 0.2) and Total bilirubin (P < 0.01, ηp2 = 0.33). MLT intake before HIIE reduced muscle damage by modulating oxidative stress and preventing overexpression of the pro-inflammatory mediators in people with obesity.

HIIE Protocols Promote Better Acute Effects on Blood Glucose and Pressure Control in People with Type 2 Diabetes than Continuous Exercise.

This study compared the acute effects of a session of different high-intensity interval exercise (HIIE) protocols and a session of moderate-intensity continuous exercise (MICE) on blood glucose, blood pressure (BP), and heart rate (HR) in people with Type 2 Diabetes Mellitus (DM2). The trial included 44 participants (age: 55.91 ± 1.25 years; BMI: 28.95 ± 0.67 kg/m2; Hb1Ac: 9.1 ± 2.3%; 76 mmol/mol) randomized into three exercise protocols based on the velocity at which maximum oxygen consumption was obtained (vVO2 max): long HIIE (2 min at 100% vV̇o2peak + 2 min of passive rest); short HIIE (30 s at 100% vV̇o2peak + 30 s of passive rest); or MICE (14 min at 70% vV̇o2peak) on a treadmill. Capillary blood glucose, BP, and HR measurements were taken at rest, during peak exercise, immediately after the end of exercise, and 10 min after exercise. Long and short HIIE protocols reduced capillary blood glucose by 32.14 mg/dL and 31.40 mg/dL, respectively, and reduced systolic BP by 12.43 mmHg and 8.73 mmHg, respectively. No significant changes were observed for MICE. HIIE was found to promote more acute effects than MICE on glycemia and BP in people with DM2.

Acute Physiological Responses to Moderate-Intensity Continuous, High-Intensity Interval, and Variable-Intensity Intermittent Exercise

ABSTRACT Purpose: This study examined acute physiological responses to moderate-intensity continuous exercise (MICE), variable-intensity intermittent exercise (VIIE), and high-intensity interval exercise (HIIE) protocol, matched for total work output in healthy adults (n = 8, age = 25.1 ± 6.0 yrs). Methods: Three experimental trials were completed in a random order. MICE was continuous exercise at 40% of peak work rate (WRpeak). VIIE consisted of sixteen 10-sec bursts at 120% WRpeak, sixteen 20-sec bursts at 60% WRpeak and recovery at 20% WRpeak interspersed throughout the protocol. HIIE consisted of eight intervals of 2 minutes at 70% WRpeak and 1 minute at 20% WRpeak. Oxygen consumption during work-intervals and time within moderate and vigorous-intensity zones determined the magnitude and duration of physiological stresses. Perceptual responses were measured by affective response and post-exercise enjoyment (PACES). Repeated-measure ANOVAs analyzed differences between trials. Statistical significance was established if p ≤ 0.05. Results: Oxygen consumption during work-intervals in VIIE was greater than MICE, but less than HIIE. VIIE and HIIE had similar duration within vigorous-intensity zone (11.1 ± 3.5 min vs. 13.5 ± 1.3 min); both were greater than MICE (4.9 ± 1.1 min). The time spent in the moderate-intensity zone was different between all trials (VIIE = 11.1 ± 2.0 min; MICE = 17.4 ± 5.2 min; HIIE = 4.9 ± 0.4 min). Affective responses were similar among all trials. Post-exercise enjoyment was greater in VIIE than HIIE; both were not different from MICE. Conclusion: These results suggests the VIIE paradigm could be a viable alternative to HIIE and MICE protocols.

Response of coagulation factors to different high intensity interval exercise protocols in young overweight men

هدف: هدف تحقیق حاضر بررسی پاسخ فاکتورهای انعقادی به پروتکل های مختلف فعالیت تناوبی در مردان دارای اضافه وزن بود.مواد و روش ها: تعداد 10مرد جوان ( شاخص توده بدنی 4/1±5/26 کیلوگرم/متر2) به عنوان آزمونی انتخاب شدند. بعد از تعیین حداکثر توان، آزمودنی ها در دو جلسه با فاصله یک هفته، پروتکل­ تناوبی با شدت 110% حداکثر توان ، 6 تکرار 30 ثانیه ای با استراحت های فعال 5/3 دقیقه ای و پروتکل تناوبی با شدت 85% حداکثر توان به صورت 6 تکرار 2 دقیقه ای با استراحت های فعال 2 دقیقه ای را اجرا کردند. قبل و بلافاصله بعد از هر پروتکل اندازه گیری­ها به عمل آمد. جهت بررسی آماری از آزمون تی مستقل و در سطح 05/0≥ P استفاده شد.یافته ها: نتایج تحقیق نشان داد یک جلسه فعالیت تناوبی با شدت بالا صرف نظر از نوع پروتکل تاثیر معنی داری بر مقادیر زمان پروترومبین نداشت (05/0P> )، اما بین پاسخ زمان پروترومبین به دو پروتکل تفاوت معنی داری را نشان داد (05/0p <). یک جلسه فعالیت تناوبی با شدت بالا تاثیر معنی داری در متغیرهای زمان نسبی ترومبوپلاستین و فیبرینوژن نداشت (05/0P>)، بررسی تفاوت پاسخ این متغیرها به دو پروتکل نیز تفاوت معنی داری را نشان نداد (05/0P>).نتیجه گیری: هر چند شدت بالای فعالیت باعث افزایش نسبی فاکتورهای انعقادی و کاهش زمان انعقاد شد ولی نوع پروتکل بر این تغییرات موثر نبود؛ احتمالا این پروتکل­ها با تغییرات اندک در فیبرینوژن به عنوان یکی از پروتئین های التهابی مرحله حاد، می توانند به عنوان شیوه تمرینی مفیدی برای افراد غیرفعال در نظر گرفته شوند.

Effects of high-intensity interval exercise and moderate-intensity continuous exercise on executive function of healthy young males

PurposeThis study compared the executive function (EF) performance induced by moderate-intensity continuous exercise (MICE) versus high-intensity interval exercise (HIIE), under two exercise modalities (i.e., running vs. cycling), and explored whether the changes in EF performance were related to the hemodynamics response of the cerebral prefrontal area of the brain. MethodsIn a randomized cross-over design, 16 male participants completed 4 main trials, i.e., 40 min of moderate-intensity continuous running (MICR) or cycling (MICC) with 60% maximal oxygen consumption (VO2max), 33 min of high-intensity interval running (HIIR) or cycling (HIIC). For HIIR or HIIC trials, the exercise intensity was 60% VO2max for the first 5 min, followed by four 4-minute bouts of exercise at 90% VO2max, separated by 3-minute active recovery at 60% VO2max. EF was assessed via the Eriksen Flanker task (EFT) before (Pre), immediately after (Post 0), and 10 min after exercise (Post 10). Functional near-infrared spectroscopy (fNIRS) measured oxygenated hemoglobin (O2Hb) and deoxygenated hemoglobin (HHb) concentrations in the prefrontal area. Each main trial measured the concentrations of blood glucose and lactate, heart rate, and rate of perceived exertion. Results(1) Compared to the reaction time in EFT during the pretest, the corresponding reaction time was shorter at Post 10 (P < 0.01) but not at Post 0 (P = 0.06). Specifically, reaction time was shorter at Post 10 than in the pretest in HIIC (P = 0.04), MICC (P = 0.01), and HIIR (P < 0.01) but not MICR. (2) The fNIRS results revealed that O2Hb concentrations in the left dorsolateral prefrontal cortex area were much lower during Post 10 than during the pretest. (3) The blood lactate concentrations were not associated with EF performance regarding both accuracy and reaction time. ConclusionCompared to the pretest, EF was greater after the 10-minute rest during recovery but not immediately after exercise. The different HIIE or MICE protocols adopted in the present study may elicit minor differences regarding their effects on EF.

Might High-Intensity Interval Exercise Be Remembered as More Pleasurable? An Attempt to Test the Peak-End Rule in the Exercise Context

Given humans' limited ability to recall past experiences for evaluation, scholars have proposed the peak-end rule stating that if perceived discomfort at the end of an aversive experience is lower than the peak discomfort experienced, the aversive experience will be remembered more positively. The purpose of this study was to evaluate the peak-end rule as applied to high-intensity interval exercise (HIIE). Participants were 30 inactive men (M age = 27.9, SD = 5.2 years). In the first session they performed a graded exercise test on cycle-ergometer to determine their maximal aerobic power (MAP) (M = 233, SD = 35W); and, in the second and third sessions, they performed two HIIE protocols in randomized order: (a) Short trial - 20-minutes of HIIE, composed of 30-second efforts at 100% of MAP interspersed by 30-seconds of passive recovery; and (b) Long trial - 20-minutes of the short trial, plus 10-minutes more of HIIE, decreasing 3% of MAP in each additional bout, resulting in 70% of MAP in the last bout. During exercise, we recorded the participants' rating of perceived exertion (RPE) and affect, using the Feeling Scale (FS). At 30-minutes post-exercise, we again recorded the participants' affect, using the Global Affect Evaluation (GAE) and their session-RPE, and we recorded their enjoyment, using the Physical Activity Enjoyment Scale (PACES). In the last session, the participants chose a favorite protocol to repeat. All sessions were interspersed by at least 72 hours. The 10-minutes extra HIIE in the Long-trial condition resulted decreased heart rate values (M = 157, SD = 13bpm to M = 144, SD = 14bpm; p < 0.001), but psychological responses during and after exercise did not differ, nor did participants' preferred HIIE protocol. As the load drop for the Long-trial was not enough to change the psychological responses during exercise, there was no difference in the retrospective evaluation as the peak-end rule would have suggested.